Message processing method and apparatus based on the SIP protocol and an IP communication system

ABSTRACT

The present invention provides a message processing method, apparatus based on the SIP Protocol and an IP communication system, wherein the method comprises: a step for processing messages from a core network, for using a SIP proxy server as a uniform access interface for SIP messages from the core network to judge and distribute the received SIP messages to corresponding application servers for processing; a step for processing messages from the application servers, for using the SIP proxy server as a uniform access interface for SIP messages from the application servers to distribute, according to instructions from the application servers, the received SIP messages to corresponding core network device for processing. Thus, with the method and system of the present invention, when the processing capability of one application server is not enough, the processing capability of the application server could be improved by expanding the number of the application servers without any need to perform modification of the configuration by the core network device.

CROSS-REFERENCE TO RELATED APPLICATIONS

This application is the U.S. National Phase application under 35 U.S.C.§371 of International Application PCT/CN2007/003659 filed Dec. 18, 2007,which claims priority to Chinese Application 200710122373.6 filed Sep.24, 2007. The entirety of the two of these applications is herebyincorporated by reference.

FILED OF THE INVENTION

The present invention relates to a session message processing method inthe IP communication network, in particular to a message processingmethod and apparatus based on the Session Initialization Protocol (SIPfor short), in the Next Generation Network (NGN for short) or the IPMultimedia System (IMS for short) network and an IP communication systemwhich uses the method and the apparatus.

BACKGROUND OF THE INVENTION

In the NGN network or the IMS network, an application server (AS forshort) is located on a core network for processing complicated servicelogic control. The performance of the application server is affected bythe complexity of the service logic and the frequency of databaseaccess. As the processing capability of one application server islimited, when the traffic is increased continuously, the number of theapplication servers needs to be expanded so as to enhance the processingperformance of the application server. From the perspective of the corenetwork, an increase in the number of the application servers is boundto bring forth an increase in the number of the IP addresses for theapplication servers, and changes in the network topological structureand in the user distribution. If the processing capability of theapplication server can be improved without any modification of theconfiguration of the core network device, the problems of theperformance bottleneck and the capacity expansion of the applicationserver will be settled effectively. Thus, the present invention isproposed to settle these problems.

SUMMARY OF THE INVENTION

The technical problem to be solved by the present invention is toprovide a message processing method and apparatus based on the SIPProtocol and an IP communication system so as to achieve distributedimplementation of large-capacity application servers in the NGN networkor the IMS network, wherein the capacity expansion and upgrading of theapplication server do not require any modification of the configurationof the core network device, and at the same time, the stability androbustness of the application server are improved.

In order to achieve the above mentioned objects, the message processingmethod based on the SIP Protocol provided in the present invention isused in a message processing system including a number of applicationservers and core network devices, the method including:

a step for processing messages from a core network, for using a SIPproxy server as a uniform access interface for SIP messages from thecore network to judge and distribute the received SIP messages tocorresponding application servers for processing;

a step for processing messages from the application servers, for usingthe SIP proxy server as a uniform access interface for SIP messages fromthe application servers to distribute, according to instructions fromthe application servers, the received SIP messages to corresponding corenetwork devices for processing.

Before the step for processing the messages from the core network andthe step for processing the messages from the application servers, themessage processing method based on the SIP Protocol further comprises astep of judging whether a message is from the core network or from anapplication server after the message is received from a network layer bya SIP proxy server, if the message is from the core network, the stepfor processing the messages from the core network is performed;otherwise, the step for processing the messages from the applicationservers is performed.

In the message processing method based on the SIP protocol, the step forprocessing the messages from the core network further comprises a stepof judging whether a to-header in the message contains a tag parameter,and whether the message is a request message, if the to-header in themessage does not contain a tag parameter and the message is a requestmessage, the SIP proxy server distributes the message to a correspondingapplication server according to a pre-configured message distributionstrategy, and simultaneously adds a sign indicating which core networkdevice the message is from at the end of the message; and if theto-header in the message contains a tag parameter or the message is aresponse message, a further step is taken to judge whether the tagparameter in the to-header in the message contains identificationinformation of the application server.

In the message processing method based on the SIP protocol, regardingthe step of judging whether the tag parameter in the to-header in themessage contains identification information of the application server,if yes, the SIP proxy server distributes the message to a correspondingapplication server, and simultaneously adds a sign indicating which corenetwork device the message is from at the end of the message; otherwise,a further step is taken to judge whether a tag parameter in afrom-header in the message contains an application server identifier.

In the message processing method based on the SIP protocol, regardingthe step of judging whether the tag parameter in the from-header in themessage contains an application server identifier, if yes, the SIP proxyserver distributes the message to a corresponding application server,and simultaneously adds a sign indicating which core network device themessage is from at the end of the message; otherwise, the message isdiscarded.

The message processing method based on the SIP protocol furthercomprises an application server survival detection step, performedthrough the SIP proxy server, for detecting failure of an applicationserver, and transferring the traffic of the application server infailure to other application servers.

The message processing method based on the SIP protocol furthercomprises a step of adjusting distribution strategy, performed throughthe SIP proxy server, for sensing the performance of an applicationserver according to the results of the survival detection, anddynamically adjusting the distribution strategy of the applicationserver according to the performance parameters of the applicationserver.

Further, the present invention also provides a message processingapparatus using the message processing method based on the SIP protocol,comprising a number of application servers and a SIP proxy server,wherein the SIP proxy server, as a uniform access interface, receivesSIP messages from a core network or application servers, and distributesthe SIP messages to corresponding application servers or core networkdevices for processing after judging the SIP messages.

In the message processing apparatus based on the SIP protocol, the SIPproxy server is further used for detecting failure of an applicationserver, and transferring the traffic of the application server infailure to other application servers.

In the message processing apparatus based on the SIP protocol, the SIPproxy server is further used for sensing the performance of theapplication server according to the results of the failure detection,and dynamically adjusting the distribution strategy of the applicationserver according to the performance parameters of the applicationserver.

Still further, the present invention further provides an IPcommunication system using the above mentioned method and apparatus, theIP communication system comprises a message processing apparatus basedon the SIP protocol, wherein, the apparatus comprises a number ofapplication servers and a SIP proxy server, the SIP proxy server, as auniform access interface, receives SIP messages from a core network orapplication servers, and distributes the SIP messages to correspondingapplication servers or core network devices for processing after judgingthe SIP messages.

Compared to the existing technology, the present invention achievesmessage interaction between a core network and application servers byadding a SIP proxy server as a uniform access interface. When theprocessing capability of one application server is not enough, theprocessing capability of the application server is improved by expandingthe number of the application servers without any need to performmodification of the configuration of the core network devices, whicheffectively solves the problems of performance bottleneck and capacityexpansion of the application server. Meanwhile, the SIP proxy server inthe present invention can also achieve the function of fault toleranceand redundancy of the application server, which realizes highreliability of the application server.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is an architecture schematic diagram of a message processingsystem based on the SIP protocol in an IP communication system accordingto the present invention;

FIG. 2 is a flow chart of a message processing method based on the SIPprotocol according to the present invention; and

FIG. 3 is a flow chart of an embodiment of the message processing methodbased on the SIP protocol according to the present invention.

DETAILED DESCRIPTION OF THE EMBODIMENTS

The technical solution of the present invention will be describedhereinafter in detail in conjunction with the drawings thereof andembodiments for a further understanding the object, solution, and effectof the present invention. However, the embodiments and the descriptionthereof shall not be construed as undue restrictions to the scope of theclaims of the present invention.

Referring to FIG. 1 which is an architecture schematic diagram of amessage processing system based on the SIP protocol in an IPcommunication system 10 according to the present invention, the IPcommunication system 10 comprises a message processing apparatus 10′based on the SIP protocol. At the front end, a SIP proxy server 100 (SIPPROXY) connected with multiple core network devices 1, 2 . . . x acts asa SIP signaling distribution device, and at the rear end of the SIPproxy server 100, there are a number of application servers (AppServer)1, 2 . . . x for processing SIP signaling and service logic. What istransmitted between the core network devices and the SIP proxy server100 is standard SIP signaling. Based on the standard SIP signaling, somespecific private fields are added in the signaling transmitted betweenthe SIP proxy server 100 and the application servers. The SIP proxyserver 100 does not process SIP messages, but just performs simplejudgment and distribution according to received SIP messages, includingdistribution to different application servers and core network devices,wherein the distribution is based on special fields in the SIPsignaling, such as a called number, a calling number, Call-ID, and anaddress of the core network device. The SIP proxy server 100 has neitherstate nor data area, thus it has a simple processing procedure and ahigh performance, and is not affected or slightly affected by calltraffic. On the contrary, an application server needs to process SIPsignaling, service logic, and database access, and when the call trafficis increased, the number of application servers needs to be increased toachieve corresponding processing performance. The present inventionachieves message interaction between the application servers and thecore network devices by adding a SIP proxy server 100 as a uniformaccess interface, and realizes large capacity distribution of theapplication servers, which can effectively settle the problems ofperformance bottleneck and capacity expansion of the application server.

Referring to FIG. 2, a message processing flow based on the SIP protocolaccording to the present invention is further described:

Step S201, the SIP proxy server 100 receives a message from a networklayer;

Step S202, it is judged whether the message is from a core network or anapplication server, if the message is from a core network, Step S203 isperformed, and if the message is from an application server, Step S210is performed.

Step S203, it is judged whether a to-header in the message from the corenetwork contains a tag parameter and whether the message is a requestmessage;

Step S204, if the to-header in the message does not contain a tagparameter and the message is a request message, the SIP proxy server 100distributes the SIP request to a specified application server accordingto a pre-configured message distribution strategy;

Step S205, if the to-header in the message contains a tag parameter orif the message is a response message, it is checked whether the tagparameter in the to-header contains identification information of theapplication server;

Step S206, if the tag parameter in the to-header contains identificationinformation of the application server, the message is directlydistributed to the application server according to the identificationinformation, and a sign indicating from which core network device themessage is received is added at the end of the message simultaneously;

Step S207, if the tag parameter in the to-header does not containidentification information of the application server, it is checkedwhether a tag parameter in a from-header in the message containsidentification information of the application server;

Step S208, if the tag parameter in the from-header containsidentification information of the application server, the message isdirectly distributed to the application server according to theidentification information, and a sign indicating from which corenetwork device the message is received is added at the end of themessage simultaneously;

Step S209, if the tag parameter in the from-header does not containidentification information of the application server, the message isdiscarded without any processing;

Step S210, the SIP proxy server 100 receives the message from anapplication server, and sends the message to corresponding core networkdevice according to an instruction from the application server.

The above mentioned message processing procedure is further explained asfollows. Upon the receipt of a message from a core network, the SIPproxy server 100 first judges whether the to-header contains a tagparameter, if the to-header does not contain a tag parameter and themessage is a request message, which indicates that the message is amessage outside a session, the SIP proxy server 100 distributes the SIPmessage to a corresponding application server according to apre-configured message distribution algorithm. In response, theapplication server will place the identifier of the application serverin the tag parameter in the to-header in the generated message. Formessages within a SIP session, the tag parameters in the to-headers arethe same. As a consequence, upon receipt of a message within a session,the SIP proxy server 100 could realize distribution of the message onlyaccording to the tag parameter in the to-header. Similarly, upon receiptof a request initiatively started by an application server, theapplication server will place its identifier in a tag parameter in thefrom-header in the message. For messages within a SIP session, the tagparameters in the from-headers are the same. As a consequence, uponreceipt of a message within a session, the SIP proxy server 100 couldrealize distribution of the message only according to the tag parameterin the from-header. Thus, the SIP proxy server 100 could realizedistribution of a message within a session according to the tagparameter in the to-header or the tag parameter in the from-header inthe message. Upon receipt of a request message without a tag parameterin the to-header, which indicates that the message is a message outsidea session, the SIP proxy server 100 could realize distribution of themessage to different application servers according to the messagedistribution strategy so as to achieve service load balance.

The distribution algorithm in the SIP proxy server 100 is configurable.The SIP proxy server can also perform survival detection for anapplication server, sense the performance of the application serveraccording to the result of the detection, and thus dynamically adjustthe distribution strategy for the application server based on theperformance parameters of the application server. If the SIP proxyserver detects a failure in one application server, it can transfer thetraffic of the application server to other application servers toachieve fault tolerance and call redundancy.

Referring to FIG. 3, the message processing method based on the SIPProtocol according to the present invention is further explainedaccording to an embodiment.

Step S301, the SIP proxy server 100 receives a message from a networklayer;

Step S302, the SIP proxy server 100 further judges whether the messageis from a core network, if the message is from a core network, Step S303is performed, otherwise, Step S310 is performed to remove the “sendss”character at the end of the message, and simultaneously sends themessage to the address specified by the “sends”.

Step S303, the SIP proxy server 100 further judges whether the to-headerin the message from the core network contains a tag parameter, andwhether the message is a request message;

Step S304, if the to-header in the message does not contain a tagparameter and the message is a request message, the message isdistributed to a corresponding application server based on a specificapplication server distribution algorithm, and simultaneously arecv_send field is added at the end.

Step S305, if the to-header in the message contains a tag parameter, orif the message is a response message, it is checked whether the tagparameter in the to-header contains SSx_ASx information;

Step S306, if the tag parameter in the to-header contains SSx_ASxinformation, the message is distributed to corresponding ASx;

Step S307, if the tag parameter in the to-header does not containSSx_ASx information, it is checked whether the tag parameter in thefrom-header in the message contains SSx_ASx information;

Step S308, if the tag parameter in the from-header contains SSx_ASxinformation, the message is distributed to corresponding ASx;

Step S309, if the tag parameter in the from-header does not containSSx_ASx information, the message is discarded.

With the method and system of the present invention, when the processingcapability of one application server is not enough, the processingcapability of the application server could be improved by expanding thenumber of the application servers, and there is no need to make anymodification of the configuration of the core network devices.Meanwhile, the SIP proxy server in the present invention detects,through a heartbeat message between the SIP proxy server and anapplication server, the processing capability and survival of the serverto realize the capability of load sharing, fault tolerance andredundancy between the application servers. Further, the SIP proxyserver system provided in the present invention provides a variety ofinformation distribution abilities, and can achieve flexible messagedistribution. The present invention is proved to be of superior effectin practical application. When the system is tested on a minicomputerwith a CPU of 1.80 GHZ and a memory of 1.0 G, 1024 caps of calls occupyabout 19.1% of the CPU. However, regarding a single application server,when 150 caps of calls are processed on a minicomputer with a CPU of1.80 GHZ and a memory of 1.0 G, 80% of the CPU is occupied. In thiscase, the problems of capacity expansion and reliability of theapplication server can be settled by expanding the number of theapplication servers.

The present invention is disclosed by a preferable embodiment as above,but it is not used to restrict the present invention. For those skilledin the art, the present invention may have various changes andvariations, without departure from the spirit and principle of thepresent invention. However, these changes and variations are allincluded in the scope of the claims of the present invention.

What is claimed is:
 1. A message processing method based on the SIPProtocol for a message processing system including a number ofapplication servers and core network devices, comprising: a step ofprocessing messages from a core network, of using a SIP proxy server asa uniform access interface for SIP messages from the core network tojudge and distribute the received SIP messages to correspondingapplication servers for processing; a step of processing messages fromthe application servers, of using the SIP proxy server as a uniformaccess interface for SIP messages from the application servers todistribute, according to instructions from the application servers, thereceived SIP messages to corresponding core network devices forprocessing, wherein the method further comprises an application serversurvival detection step, performed through the SIP proxy server, fordetecting failure of an application server and transferring the trafficof the application server in the event of failure to other applicationservers, and wherein the step for processing the messages from the corenetwork further comprises judging whether a to-header in the messagecontains a tag parameter, and whether the message is a request message,if the to-header in the message does not contain a tag parameter and themessage is a request message, the SIP proxy server distributes themessage to a corresponding application server according to apre-configured message distribution strategy, and simultaneously adds asign indicating which core network device the message is from at the endof the message, and if the to-header in the message contains a tagparameter or the message is a response message, a further step is takento judge whether the tag parameter in the to-header in the messagecontains identification information of the application server.
 2. Themessage processing method based on the SIP Protocol according to claim1, wherein, before the step of processing the messages from the corenetwork and the step of processing the messages from the applicationservers, the method further comprises: a step of judging whether amessage is from the core network or from an application server after themessage is received from a network layer by the SIP proxy server, if themessage is from the core network, performing the step of processing themessages from the core network, otherwise, performing the step ofprocessing the messages from the application servers.
 3. The messageprocessing method based on the SIP Protocol according to claim 1,wherein, regarding the step of judging whether the tag parameter in theto-header in the message contains identification information of theapplication server, if yes, the SIP proxy server distributes the messageto a corresponding application server, and simultaneously adds a signindicating which core network device the message is from at the end ofthe message; otherwise, a further step is taken to judge whether a tagparameter in a from-header in the message contains an application serveridentifier.
 4. The message processing method based on the SIP Protocolaccording to claim 3, wherein, regarding the step of judging whether thetag parameter in the from-header in the message contains an applicationserver identifier, if yes, the SIP proxy server distributes the messageto a corresponding application server, and simultaneously adds a signindicating which core network device the message is from at the end ofthe message; otherwise, the message is discarded.
 5. The messageprocessing method based on the SIP Protocol according to claim 1,wherein, the method further comprises a step of adjusting distributionstrategy, performed through the SIP proxy server, of sensing theperformance of the application server according to the results of thesurvival detection, and dynamically adjusting the distribution strategyof the application server according to the performance parameters of theapplication server.
 6. A message processing apparatus using the messageprocessing method based on the SIP protocol according to claim 1,comprising a number of application servers and a SIP proxy server,wherein the SIP proxy server, as a uniform access interface, receivesSIP messages from a core network or application servers, and distributesthe SIP messages to corresponding application servers or core networkdevices for processing after judging the SIP messages, wherein the SIPproxy server is further used for detecting failure of an applicationserver, and transferring the traffic of the application server in theevent of failure to other application servers, and wherein the SIP proxyserver is further used for performing following steps for processing themessages from the core network: judging whether a to-header in themessage contains a tag parameter, and whether the message is a requestmessage, if the to-header in the message does not contain a tagparameter and the message is a request message, the SIP proxy serverdistributing the message to a corresponding application server accordingto a pre-configured message distribution strategy, and simultaneouslyadding a sign indicating which core network device the message is fromat the end of the message, and if the to-header in the message containsa tag parameter or the message is a response message, further judgingwhether the tag parameter in the to-header in the message containsidentification information of the application server.
 7. The messageprocessing apparatus based on the SIP protocol according to claim 6wherein, the SIP proxy server is further used for sensing theperformance of the application server according to the results of thefailure detection, and dynamically adjusting the distribution strategyof the application server according to the performance parameters of theapplication server.
 8. An IP communication system using the messageprocessing method based on the SIP protocol according to claim 1,comprising a message processing apparatus based on the SIP protocolwherein, the apparatus comprises a number of application servers and aSIP proxy server, the SIP proxy server, as a uniform access interface,receives SIP messages from a core network or application servers, anddistributes the SIP messages to corresponding application servers orcore network devices for processing after judging the SIP messages,wherein the SIP proxy server is further used for detecting failure of anapplication server, and transferring the traffic of the applicationserver in the event of failure to other application servers, and whereinthe SIP proxy server is further used for performing following steps forprocessing the messages from the core network: judging whether ato-header in the message contains a tag parameter, and whether themessage is a request message, if the to-header in the message does notcontain a tag parameter and the message is a request message, the SIPproxy server distributing the message to a corresponding applicationserver according to a pre-configured message distribution strategy, andsimultaneously adding a sign indicating which core network device themessage is from at the end of the message, and if the to-header in themessage contains a tag parameter or the message is a response message,further judging whether the tag parameter in the to-header in themessage contains identification information of the application server.9. A message processing apparatus using the message processing methodbased on the SIP protocol according to claim 2, comprising a number ofapplication servers and a SIP proxy server, wherein the SIP proxyserver, as a uniform access interface, receives SIP messages from a corenetwork or application servers, and distributes the SIP messages tocorresponding application servers or core network devices for processingafter judging the SIP messages, wherein the SIP proxy server is furtherused for detecting failure of an application server, and transferringthe traffic of the application server in the event of failure to otherapplication servers, and wherein the SIP proxy server is further usedfor performing following steps for processing the messages from the corenetwork: judging whether a to-header in the message contains a tagparameter, and whether the message is a request message, if theto-header in the message does not contain a tag parameter and themessage is a request message, the SIP proxy server distributing themessage to a corresponding application server according to apre-configured message distribution strategy, and simultaneously addinga sign indicating which core network device the message is from at theend of the message, and if the to-header in the message contains a tagparameter or the message is a response message, further judging whetherthe tag parameter in the to-header in the message containsidentification information of the application server.
 10. A messageprocessing apparatus using the message processing method based on theSIP protocol according to claim 1, comprising a number of applicationservers and a SIP proxy server, wherein the SIP proxy server, as auniform access interface, receives SIP messages from a core network orapplication servers, and distributes the SIP messages to correspondingapplication servers or core network devices for processing after judgingthe SIP messages, wherein the SIP proxy server is further used fordetecting failure of an application server, and transferring the trafficof the application server in the event of failure to other applicationservers, and wherein the SIP proxy server is further used for performingfollowing steps for processing the messages from the core network:judging whether a to-header in the message contains a tag parameter, andwhether the message is a request message, if the to-header in themessage does not contain a tag parameter and the message is a requestmessage, the SIP proxy server distributing the message to acorresponding application server according to a pre-configured messagedistribution strategy, and simultaneously adding a sign indicating whichcore network device the message is from at the end of the message, andif the to-header in the message contains a tag parameter or the messageis a response message, further judging whether the tag parameter in theto-header in the message contains identification information of theapplication server.
 11. A message processing apparatus using the messageprocessing method based on the SIP protocol according to claim 3,comprising a number of application servers and a SIP proxy server,wherein the SIP proxy server, as a uniform access interface, receivesSIP messages from a core network or application servers, and distributesthe SIP messages to corresponding application servers or core networkdevices for processing after judging the SIP messages, wherein the SIPproxy server is further used for detecting failure of an applicationserver, and transferring the traffic of the application server in theevent of failure to other application servers, and wherein the SIP proxyserver is further used for performing following steps for processing themessages from the core network: judging whether a to-header in themessage contains a tag parameter, and whether the message is a requestmessage, if the to-header in the message does not contain a tagparameter and the message is a request message, the SIP proxy serverdistributing the message to a corresponding application server accordingto a pre-configured message distribution strategy, and simultaneouslyadding a sign indicating which core network device the message is fromat the end of the message, and if the to-header in the message containsa tag parameter or the message is a response message, further judgingwhether the tag parameter in the to-header in the message containsidentification information of the application server.
 12. A messageprocessing apparatus using the message processing method based on theSIP protocol according to claim 4, comprising a number of applicationservers and a SIP proxy server, wherein the SIP proxy server, as auniform access interface, receives SIP messages from a core network orapplication servers, and distributes the SIP messages to correspondingapplication servers or core network devices for processing after judgingthe SIP messages, wherein the SIP proxy server is further used fordetecting failure of an application server, and transferring the trafficof the application server in the event of failure to other applicationservers, and wherein the SIP proxy server is further used for performingfollowing steps for processing the messages from the core network:judging whether a to-header in the message contains a tag parameter, andwhether the message is a request message, if the to-header in themessage does not contain a tag parameter and the message is a requestmessage, the SIP proxy server distributing the message to acorresponding application server according to a pre-configured messagedistribution strategy, and simultaneously adding a sign indicating whichcore network device the message is from at the end of the message, andif the to-header in the message contains a tag parameter or the messageis a response message, further judging whether the tag parameter in theto-header in the message contains identification information of theapplication server.
 13. An IP communication system using the messageprocessing method based on the SIP protocol according to claim 2,comprising a message processing apparatus based on the SIP protocol,wherein, the apparatus comprises a number of application servers and aSIP proxy server, the SIP proxy server, as a uniform access interface,receives SIP messages from a core network or application servers, anddistributes the SIP messages to corresponding application servers orcore network devices for processing after judging the SIP messages,wherein the SIP proxy server is further used for detecting failure of anapplication server, and transferring the traffic of the applicationserver in the event of failure to other application servers, and whereinthe SIP proxy server is further used for performing following steps forprocessing the messages from the core network: judging whether ato-header in the message contains a tag parameter, and whether themessage is a request message, if the to-header in the message does notcontain a tag parameter and the message is a request message, the SIPproxy server distributing the message to a corresponding applicationserver according to a pre-configured message distribution strategy, andsimultaneously adding a sign indicating which core network device themessage is from at the end of the message, and if the to-header in themessage contains a tag parameter or the message is a response message,further judging whether the tag parameter in the to-header in themessage contains identification information of the application server.14. An IP communication system using the message processing method basedon the SIP protocol according to claim 1, comprising a messageprocessing apparatus based on the SIP protocol, wherein, the apparatuscomprises a number of application servers and a SIP proxy server, theSIP proxy server, as a uniform access interface, receives SIP messagesfrom a core network or application servers, and distributes the SIPmessages to corresponding application servers or core network devicesfor processing after judging the SIP messages, wherein the SIP proxyserver is further used for detecting failure of an application server,and transferring the traffic of the application server in the event offailure to other application servers, and the SIP proxy server isfurther used for performing following steps for processing the messagesfrom the core network: judging whether a to-header in the messagecontains a tag parameter, and whether the message is a request message,if the to-header in the message does not contain a tag parameter and themessage is a request message, the SIP proxy server distributing themessage to a corresponding application server according to apre-configured message distribution strategy, and simultaneously addinga sign indicating which core network device the message is from at theend of the message, and if the to-header in the message contains a tagparameter or the message is a response message, further judging whetherthe tag parameter in the to-header in the message containsidentification information of the application server.
 15. An IPcommunication system using the message processing method based on theSIP protocol according to claim 3, comprising a message processingapparatus based on the SIP protocol, wherein, the apparatus comprises anumber of application servers and a SIP proxy server, the SIP proxyserver, as a uniform access interface, receives SIP messages from a corenetwork or application servers, and distributes the SIP messages tocorresponding application servers or core network devices for processingafter judging the SIP messages, wherein the SIP proxy server is furtherused for detecting failure of an application server, and transferringthe traffic of the application server in the event of failure to otherapplication servers, and wherein the SIP proxy server is further usedfor performing following steps for processing the messages from the corenetwork: judging whether a to-header in the message contains a tagparameter, and whether the message is a request message, if theto-header in the message does not contain a tag parameter and themessage is a request message, the SIP proxy server distributing themessage to a corresponding application server according to apre-configured message distribution strategy, and simultaneously addinga sign indicating which core network device the message is from at theend of the message, and if the to-header in the message contains a tagparameter or the message is a response message, further judging whetherthe tag parameter in the to-header in the message containsidentification information of the application server.
 16. An IPcommunication system using the message processing method based on theSIP protocol according to claim 4, comprising a message processingapparatus based on the SIP protocol, wherein, the apparatus comprises anumber of application servers and a SIP proxy server, the SIP proxyserver, as a uniform access interface, receives SIP messages from a corenetwork or application servers, and distributes the SIP messages tocorresponding application servers or core network devices for processingafter judging the SIP messages, wherein the SIP proxy server is furtherused for detecting failure of an application server, and transferringthe traffic of the application server in the event of failure to otherapplication servers, and wherein the SIP proxy server is further usedfor performing following steps for processing the messages from the corenetwork: judging whether a to-header in the message contains a tagparameter, and whether the message is a request message, if theto-header in the message does not contain a tag parameter and themessage is a request message, the SIP proxy server distributing themessage to a corresponding application server according to apre-configured message distribution strategy, and simultaneously addinga sign indicating which core network device the message is from at theend of the message, and if the to-header in the message contains a tagparameter or the message is a response message, further judging whetherthe tag parameter in the to-header in the message containsidentification information of the application server.